The proposed study is a PORT II effectiveness trial, using a quasi- experimental design, to evaluate the cost=effectiveness of alternative approaches to improving care for depression in prepaid group practices and to obtain information on the linkages between processes of care and patient outcomes in both primary care and mental health specialty settings. Major depression and chronic depression are common in health care settings, strongly affect functioning, and have high social and economic costs. Efficacious treatments for depression exist, but are often not applied, especially in general medical settings. Can care for depression be improved cost-effectively? To address this question, we will implement and evaluate interventions designed to increase the exposure of patients to three treatments (appropriate antidepressant medication or interpersonal counseling in general medical clinics; and maintenance therapy for recurrent and chronic depression in mental health specialty settings) that are of established efficacy. The interventions leave treatment decisions with the usual care provider but use clinical protocols, changes in practice structure, and patient and provider education to enable more appropriate care. We assess intervention effects, compared to care as usual, on quality of care, patient clinical and functioning outcomes and satisfaction with care, use of services, direct and indirect costs, and cost-effectiveness of care and cost-utilities. In addition, we will examine effects of specific depression treatments that are enhanced by the interventions on outcomes. The study will be conducted by an interdisciplinary research team involving a core RAND group and collaborators from multiple institutions and sites. General medical clinics in prepaid group practices in three U.S. sites will be randomly assigned to intervention (medication or counseling) or care as usual. Within these clinics, patients with current major depression or chronic depression will be identified by study staff and followed for two years with periodic self-report questionnaires and telephone interviews. Within mental health clinics, patients with recurrent or chronic depression will be randomly assigned to a continuity/case management intervention or care as usual. Patients will be followed for two years. The analysis will include bivariate analyses, multiple regression analyses, and decision analysis to identify effects of the interventions (relative to care as usual)_ and linkages between treatments and outcomes. We hypothesize that each intervention will be cost effective compared to care as usual.